Applicants claim priority under 35 U.S.C. xc2xa7119 of German Application Nos. 197 25 638.4 and 197 44 147.5 filed Jun. 18, 1997 and Oct. 7, 1997, respectively. Applicants also claim priority under 35 U.S.C. xc2xa7120 of PCT/DE98/01460 filed May 28, 1998. The international application under PCT article 21(2) was not published in English.
1. Field of the Invention
The invention relates to a rail arrangement for a rail superstructure such as a fixed railroad, comprising an elastic intermediate plate, which is located between the foot of the rail and a hard support (for example concrete support plates, steel ties, concrete ties), and which is provided in most cases with two through-extending holes for the screws to fasten the rails, whereby the elastic intermediate plate
consists of a single-piece vulcanisate produced from a rubber mixture based on natural rubber (NR), epoxidized natural rubber (ENR), isoprene rubber (IR), butadiene rubber (BR), acrylate rubber (ACM), styrene-butadiene rubber (SBR), or mixtures of said types of rubber, in particular NR/SBR or NR/BR mixtures, as well as the usual mixture ingredients such as fillers, plasticizers, anti-aging agents as well as additional additives, if necessary;
has a substantially plane surface, whereas its bottom side has an edge extending all around, said edge being provided in most cases with a drainage duct extending in the transverse direction relative to the rail, whereby the edge is a system of protrusions and recesses with a preferably substantially mirror-symmetric overall structure based on the center planes extending in the transverse and longitudinal directions of the rail, whereby the bottom side is in most cases seated on the hard support;
and has three zones extending substantially parallel with the longitudinal direction of the rail, whereby the center zone has a different structure with respect to the system of protrusions and recesses than the two side zones having the same structure, in a way such that the center zones have greater rubber-elastic deformability than the two side zones.
2. The Prior Art
A similar rail arrangement is known from EP-A-0 541 884. It has been proposed in connection with said document, for example to provide the elastic intermediate plate with blind holes or zigzag-shaped grooves, whereby said elements forming the recesses occur more frequently within the center zone than within the two side zones, which leads to the fact that the center zone has greater rubber-elastic deformability than the two side zones.
Also, an elastic intermediate plate, provided with a protrusion system, is known from DE 195 04 937.
A considerable component of long-distance passenger rail traffic is already realized at the present time on so-called high-speed railroad lines in a number of countries, in particular in France, Japan and Germany. Due to the new construction of such railroad lines, which are being built within the framework of coupling national high-speed lines in Europe to form an international system, including at the same time long-distance freight railroad transport (mixed utilization of the railway lines), said development continues to make progress.
The expenditure to maintain and service such high-speed lines is justifiable and long-term utilization of such lines at low cost is possible only if such high-speed railway lines are built as so-called xe2x80x9cfixed lanesxe2x80x9d on earth structures and in tunnels and on bridges, as opposed to the classic crushed-stone ballast surface. Now, in order to obtain optimal riding comfort, low vibration and low noise molestation of the railwayside population, low dynamic stress for the railway lanes, and high availability of the railway tracks, the elastic intermediate plate has to satisfy the following requirements, namely:
static secant stiffness Cstat=10 to 30 kN/mm, in particular 15 to 25 kN/mm (lower limit 15 kN, upper limit 50 kN); and
dynamic stiffening factor xc3xa6xe2x89xa62.5, in particular xe2x89xa61.5.
Taking into account the resistance to fatigue and the fatigue limit (useful life), said requirements can not be satisfied with a single-piece intermediate plate produced as a molded article based on TPE material. The values specified for Cstat as shown above with a compatible dynamic stiffening factor over the required useful life can not be achieved with a TPE material without distinctly increasing the structural height. Said requirements can be met only in connection with vulcanisates produced from a rubber mixture particularly with the use of the NR, ENR, IR, BR, ACM, SBR, NR/SBR or NR/BR types of rubber, including a suitable construction of the elastic intermediate plate.
The elastic intermediate plate as defined by the invention is characterized by the following constructional design features:
The recesses within the three zones are designed as inactive surfaces forming at the same time the bottom, the latter representing the closed limitation relative to the top side of the elastic intermediate plate, whereby the inactive surfaces within the center zone are disposed deeper than the ones located in the two side zones as well have within one zone a substantially constant depth.
The active surfaces of the protrusions within the center zone have a smaller overall surface than the ones of the protrusions within each of the side zones.
The two side zones each occupy a larger surface area than the center zone.